The mechanisms causing European heatwaves in recent years, particularly their differences among several heatwaves, are poorly understood. Here, atmospheric circulation anomalies and soil moisture‐temperature coupling during the summer 2018 heatwave are comprehensively examined and compared with the 2003 and 2010 heatwaves using ERA5 reanalysis, model simulations and eddy covariance flux measurements. We show that the 2018 heatwave successively affected northern and central Europe, and the peak temperature in Finland and northwest Russia broke historical records of the past 40 years. Although three heatwaves were all initially triggered by atmospheric circulation anomalies, the strong moisture–temperature coupling were found to further strengthen the 2003 and 2010 heatwaves. This coupling was also strong in central Europe during 2018 heatwave, but was weak in the northern European center of the heatwaves. The high temperature in 2018 was mainly due to increases in the amount of net surface radiation caused by the clear skies associated with reduced precipitation. Furthermore, we also find that landcover plays a critical role in determining the occurrence and strength of soil moisture‐temperature coupling. Cropland/grassland depletes soil moisture more readily than forests, thereby triggering a more rapid release of sensible fluxes as observed during 2018 heatwave.

中文翻译：

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2003年，2010年和2018年引起欧洲夏季热浪的机制的异同

近年来，引起欧洲热浪的机制，特别是它们在几个热浪之间的差异，了解得很少。在此，我们使用ERA5再分析，模型模拟和涡度协方差通量测量，全面检查了2018年夏季热浪期间的大气环流异常和土壤湿度-温度耦合，并将其与2003年和2010年的热浪进行了比较。我们显示，2018年的热浪先后影响了北欧和中欧，芬兰和俄罗斯西北部的峰值温度打破了过去40年的历史记录。尽管最初由大气环流异常触发了三个热浪，但发现强烈的水温耦合进一步加强了2003年和2010年的热浪。在2018年的热浪中，这种耦合在中欧也很强，但是在北欧的热浪中却很弱。2018年的高温主要是由于晴朗的天空与降水减少相关的净表面辐射量增加所致。此外，我们还发现，土地覆盖物在确定土壤水分-温度耦合的发生和强度方面起着至关重要的作用。农田/草原比森林更容易消耗土壤水分，从而触发了更快的通量释放，如2018年热浪所观察到的。我们还发现，地表覆盖物在决定土壤水温耦合的发生和强度方面起着至关重要的作用。耕地/草原比森林更容易消耗土壤水分，从而触发2018年热浪期间更快地释放出合理的通量。我们还发现，地表覆盖物在决定土壤水温耦合的发生和强度方面起着至关重要的作用。耕地/草原比森林更容易消耗土壤水分，从而触发2018年热浪期间更快地释放出合理的通量。